Air inlet device comprising at least one helical partition and aircraft comprising at least one air inlet device of this kind

The subject matter herein relates to an air inlet device comprising at least one helical partition, and to an aircraft comprising at least one air inlet device of this kind.

According to one embodiment, an aircraftcomprises a fuselage, wingsprovided on either side of the fuselage, and propulsion assembliesconnected to the wings via pylons. The aircraftcomprises at least one air inlet devicethat can be seen inand that opens out at an aerodynamic surfacethat is in contact with an air flowwhen the aircraftis in flight. This air inlet deviceis configured to capture a portion of the air flowand direct it towards an on-board system of the aircraft. The aerodynamic surfacemay be provided on the fuselage, a wing, a propulsion assemblyor a pylon.

According to one configuration, the air inlet devicecomprises an inlet ductthat extends between a first end.connected to the aerodynamic surfaceand a second end., and a valveconnected to the second end.of the inlet ductand configured to occupy an open state in which the valveallows an air flow conveyed by the inlet ductto pass through it, and a closed state in which the valveblocks the air flow in the inlet duct.

According to one configuration, the first end., which opens out at the aerodynamic surface, is flared and forms a flush-type air intake.

The air inlet deviceis optimized to reduce the drag of the aircraft when the valveis in the open state.

When the valveis in the closed state, the inlet ductand the closed valveform a cavity, shown schematically in, which opens out at the aerodynamic surface. The air flowpassing above the cavitygenerates a vibro-acoustic phenomenon with a frequency in the order of 200 Hz which results in aerodynamic noise.

The disclosure herein aims to overcome all or some of the drawbacks of the prior art.

To this end, the disclosure herein relates to an air inlet device comprising an inlet duct that extends between a first end intended to open out at an aerodynamic surface and a second end, as well as a valve connected to the second end of the inlet duct.

According to the disclosure herein, the air inlet device comprises at least one helical partition positioned within the inlet duct, having an outer edge in contact with the inlet duct and delimiting at least one helical duct within the inlet duct.

The helical partition serves to increase the distance travelled by an air flow entering the inlet duct before it reaches the valve in the closed state, which reduces the resonance frequency of the air flow entering the inlet duct and, ultimately, reduces noise emissions.

According to another feature, the air inlet device comprises an axial support about which each helical partition is wound.

According to another feature, each helical partition is connected to the axial support and/or to the inlet duct in a sealing manner.

According to another feature, the inlet duct comprises at least a first section delimited by a substantially cylindrical tubular wall that extends from the second end of the inlet duct and has an axis of revolution.

According to another feature, each helical partition is positioned within the first section of the inlet duct and has a length substantially equal to that of the first section.

According to another feature, the axial support is a cylindrical rod having an axis coincident with the axis of revolution of the tubular wall, the axial support having a length greater than or equal to that of the first section of the inlet duct.

According to another feature, the air inlet device comprises a plurality of helical partitions.

According to another feature, the helical partitions have the same winding direction, the same pitch and are spaced from one another by the same spacing.

According to another feature, the air inlet device comprises two helical partitions, each having an upstream edge located at the first end of the inlet duct or closest thereto, the upstream edges of the two helical partitions being aligned.

The disclosure herein also relates to an aircraft comprising at least one aerodynamic surface and an air inlet device according to any one of the preceding features, which opens out at the aerodynamic surface.

According to one embodiment shown in, an aircraft comprises at least one aerodynamic surfaceand at least one air inlet device.

The aerodynamic surfacehas an outer face Fover which an air flowflows in a flow direction when the aircraft is in flight. The aerodynamic surfacemay be provided on the fuselage, a wing, a propulsion assembly or a pylon of the aircraft.

Although described in the context of an aircraft, the disclosure herein is not limited to this application. The air inlet devicemay equip any type of vehicle and open out at an aerodynamic surface of a vehicle.

The air inlet devicecomprises an inlet ductwhich extends between a first end., also referred to as an air intake, connected to the aerodynamic surface, and a second end., and a valveconnected to the second end.of the inlet ductand configured to occupy an open state in which the valveallows an air flow conveyed by the inlet ductto pass through it, and a closed state in which the valveblocks the air flow in the inlet duct.

According to one configuration, the first end., which forms the air intake of the inlet duct, opens out at the aerodynamic surfaceand is flared in the direction of the outer face Fof the aerodynamic surface. According to this configuration, the first end.of the inlet ductforms a flush-type air intake.

When the valveis in the closed state, the inlet ductand the valvein the closed state form a cavitywhich opens out at the aerodynamic surface.

This cavityis delimited by the inlet ductand a bottom(corresponding to the valvein the closed state) that is spaced apart from the aerodynamic surface.

In the case of a flush-type air intake, the inlet ductcomprises a first section delimited by a substantially cylindrical tubular wallthat extends from the second end.of the inlet duct, and a second section delimited by a flared connecting wall′ connecting the tubular walland the aerodynamic surface.

The tubular wallhas an axis of revolution Athat is substantially parallel to an intake direction DD, which may be perpendicular or inclined relative to the outer face Fof the aerodynamic surface. By way of example, the reference direction DD forms an angle of approximately 60° with the outer face Fof the aerodynamic surface.

According to one arrangement, the bottomis substantially perpendicular to the reference direction DD and to the axis of revolution A.

As illustrated in, the inlet ducthas a depth Lcorresponding to a distance measured along the axis of revolution Abetween a surface containing the outer face Fof the aerodynamic surfaceand the bottom, as well as a volume V. The first section of the inlet ductdelimited by the tubular wallhas a length L.

According to a simplified schematic representation shown in, the inlet ductcomprises only a first section directly connected to the aerodynamic surfaceand does not comprise a connecting wall′. In addition, the axis of revolution Aof the tubular wallis substantially perpendicular to the outer face Fof the aerodynamic surface. In this case, the depth Lis substantially equal to the length Lof the tubular wall.

When the axis Ais inclined relative to the normal to the outer face F, as illustrated in, the inlet ductmay comprise two sections delimited by a tubular walland a connecting wall′. In this case, the depth Lis greater than the length L.

The disclosure herein is of course not limited to these embodiments of the air inlet device. Whatever the embodiment, the air inlet devicecomprises an inlet ductthat extends between a first end.that opens out at an aerodynamic surfaceand a second end., and a valveconnected to the second end.of the inlet ductand configured to occupy an open state in which the valveallows an air flow conveyed by the inlet ductto pass through it, and a closed state in which the valveblocks the air flow in the inlet duct. According to a preferred embodiment, the inlet ductcomprises at least a first section delimited by a substantially cylindrical tubular wallthat extends from the second end.of the inlet ductand has an axis of revolution A.

According to a particular feature of the disclosure herein, the air inlet devicecomprises an axial supportpositioned along the axis of revolution Aof the tubular wallof the inlet duct, and at least one helical partitionpositioned around the axial supportand extending between an inner edge.connected to the axial supportand an outer edge.adjacent to the inlet duct. This helical partitionserves to increase the distance travelled by an air flow entering the inlet ductbefore it reaches the bottom, thereby reducing the resonance frequency of the air flow entering the inlet ductand ultimately reducing noise emissions.

According to one configuration, the axial supporthas a length greater than or equal to the length Lof the first section of the inlet ductdelimited by the tubular wall.

According to one embodiment, the axial supportis a cylindrical rod that has an axis coinciding with the axis of revolution Aof the tubular wall.

According to one configuration, each helical partitionis sealingly connected to the axial supportand/or to the inlet duct. Each helical partitionextends within the first section of the inlet ductdelimited by the tubular walland has a length substantially equal to that of the first section. In a variant, at least one helical partitionextends into the second section of the inlet ductdelimited by the flared connecting wall′.

According to one embodiment, shown in particular in, the air inlet devicecomprises multiple helical partitions,′. These partitions have the same winding direction around the same axial support, the same pitch and are spaced from one another by the same spacing.

According to a configuration shown in, the air inlet devicecomprises two helical partitions,′ that divide the inlet ductinto two helical ducts,′. As schematically illustrated in, the two helical ducts,′ have substantially identical lengths Lwhich are clearly greater than the depth Lof the cavity, as well as substantially identical volumes V, each volume Vbeing substantially equal to half the volume Vof the cavity.

Each helical partition,′ has an upstream edge.,.′ connecting the inner and outer edges.,., located at the first end.or closest thereto.

According to one arrangement, each upstream edge.,.′ is substantially parallel to the flow direction of the air flowflowing over the outer face Fof the aerodynamic surface. When the air inlet devicecomprises two helical partitions, their upstream edges.,.′ are aligned and substantially parallel to the flow direction of the air flowflowing over the outer face Fof the aerodynamic surface.

Each helical partition,′ is wound in a winding direction around the axial support. According to a first variant, the winding direction of each helical partition,′ is clockwise. According to a second variant, the winding direction of each helical partition,′ is anti-clockwise.

Whatever the embodiment, the air inlet device comprises at least one helical partition,′ that has an outer edge.in contact with the inlet duct, the helical partition,′ being configured to delimit within the inlet ductat least one helical duct,′. The duct has a length L, a volume V, and a passage cross-section S.

It is possible to adjust the length Lof the helical ducts,′ by modifying the pitch of the helical partitions,′. Hence, the smaller the pitch of the helical partitions,′, the greater the length Lof the helical ducts,′, and the lower the resulting resonance frequency.

It is also possible to adjust the volume Vand the passage cross-section Sof the helical ducts,′ by modifying the number of helical partitions,′. Accordingly, the greater the number of helical partitions,′, the smaller the volume Vand the passage cross-section Sof each helical duct,′, and the lower the resulting resonance frequency.

Hence, it is possible to tune the resonance frequency of an air inlet deviceby adjusting at least one parameter from among: the number of helical partitions,′, the pitch of each helical partition,′, the winding direction of each helical partition,′ and the geometry of each helical partition,′ at the first end.(corresponding to the inlet of the inlet duct).

While at least one example embodiment of the invention(s) is disclosed herein, it should be understood that modifications, substitutions, and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the example embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a”, “an” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.